For documentation and information about some of the methods employed in Brent's demo, see Creating Dialogs by API

'**********************************************************************
' Container Control Demo
' By Brent D. Thorn, Nov. 2004
' This code is released to the public domain.
' No credit to the author is necessary.
'**********************************************************************

    If Val(Version$) < 4 Then
        Notice "Code requires LB 4.0 or later."
        End
    End If

    Global ghContainer ' HWND of container.

    NoMainWin

    WindowWidth = 350
    WindowHeight = 350
    UpperLeftX = (DisplayWidth - WindowWidth) / 2
    UpperLeftY = (DisplayHeight - WindowHeight) / 2

    Button      #p.btn1, "Show Container", ShowHide, UL, 10, 20

    Checkbox    #p.chk1, "Checkbox", Handler1, Handler1, 10, 10, 100, 20
    RadioButton #p.opt1, "Top", ToTop, Handler1, 10, 30, 100, 20
    RadioButton #p.opt2, "Middle", ToMid, Handler1, 10, 50, 100, 20
    RadioButton #p.opt3, "Bottom", ToBot, Handler1, 10, 70, 100, 20

    Open "Container Demo" For Window As #p

    #p "TrapClose Quit"
    #p.opt1 "Set"

    ' Create a hidden container 150x150 in size.
    hInstance = GetWindowLong(HWnd(#p), _GWL_HINSTANCE)

    ghContainer = CreateContainer(0, 0, 150, 0, 150, 150, HWnd(#p), hInstance, 0)

    ' Have container "adopt" controls.
    Call SetParent HWnd(#p.chk1), ghContainer
    Call SetParent HWnd(#p.opt1), ghContainer
    Call SetParent HWnd(#p.opt2), ghContainer
    Call SetParent HWnd(#p.opt3), ghContainer

    Call DoEvents

Sub DoEvents
  [localLoop]
    Scan
    CallDLL #kernel32, "Sleep", 50 As Long, r As void
    GoTo [localLoop]
End Sub

Sub ShowHide Handle$
    CallDLL #user32, "IsWindowVisible", ghContainer As ULong,_
      itis As Long
    If itis Then
        cmd = _SW_HIDE
        #Handle$ "Show Container"
    Else
        cmd = _SW_SHOW
        #Handle$ "Hide Container"
    End If

    CallDLL #user32, "ShowWindow", ghContainer As ULong,_
    cmd As Long, r As Long
End Sub

Sub ToTop Handle$
    Call MoveWindow ghContainer, 150, 0
End Sub

Sub ToMid Handle$
    Call MoveWindow ghContainer, 150, 100
End Sub

Sub ToBot Handle$
    Call MoveWindow ghContainer, 150, 200
End Sub

Sub Quit Handle$
    Close #Handle$
    End
End Sub

Sub Handler1 Handle$
End Sub

'**********************************************************************
' Container Management
'**********************************************************************

Function CreateContainer( ExStyle, Style, X, Y, Width, Height, hParent, hInstance, lParam )
'-- Purpose:  Creates a child dialog box for use as a container object
'             for controls. Controls must be "adopted" using SetParent.
'-- Returns:  Window handle (HWND) of the newly-created container.
'-- Depends:  ContainerProc(), HIWORD(), LOWORD(), MulDiv()

    ' Get dialog base units.
    ' They're used to convert pixels to dialog units.
    CallDLL #user32, "GetDialogBaseUnits", r As ULong
    baseX = LOWORD(r)
    baseY = HIWORD(r)

    ' Initialize dialog template struct.
    Struct DLGTEMPLATE, _
        style As ULong, _
        dwExtendedStyle As ULong, _
        cdit As Word, _
        x As Short, _
        y As Short, _
        cx As Short, _
        cy As Short, _
        menus As Word, _ 'pseudo element
        class As Word, _ 'pseudo element
        title As Word    'pseudo element

    DLGTEMPLATE.style.struct = Style Or _WS_CHILDWINDOW Or _DS_CONTROL
    DLGTEMPLATE.dwExtendedStyle.struct = ExStyle Or _WS_EX_CONTROLPARENT
    DLGTEMPLATE.cdit.struct = 0
    DLGTEMPLATE.x.struct = MulDiv(X, 4, baseX)
    DLGTEMPLATE.y.struct = MulDiv(Y, 8, baseY)
    DLGTEMPLATE.cx.struct = MulDiv(Width, 4, baseX)
    DLGTEMPLATE.cy.struct = MulDiv(Height, 8, baseY)
    DLGTEMPLATE.menus.struct = 0
    DLGTEMPLATE.class.struct = 0
    DLGTEMPLATE.title.struct = 0

    ' Template must be in global memory space.
    cbDT = Len(DLGTEMPLATE.struct)
    CallDLL #kernel32, "GlobalAlloc", _GMEM_MOVEABLE As ULong,_
     cbDT As ULong, hDT As ULong
    CallDLL #kernel32, "GlobalLock", hDT As ULong, pDT As ULong

    ' Copy struct to global memory.
    CallDLL #kernel32, "RtlMoveMemory", pDT As ULong, DLGTEMPLATE As Struct,_
    cbDT As Long, r As void

    ' Get pointer to ContainerProc().
    Callback lpDlgProc, ContainerProc( ULong, ULong, ULong, ULong ), ULong

    ' Create the modeless, child dialog box.
    CallDLL #user32, "CreateDialogIndirectParamA", hInstance As Long,_
    pDT As ULong, hParent As ULong, lpDlgProc As ULong, lParam As Long,_
    hDlg As ULong

    ' Memory is no longer needed. Let's clean up.
    CallDLL #kernel32, "GlobalUnlock", hDT As ULong, r As Long
    CallDLL #kernel32, "GlobalFree", hDT As ULong, r As ULong

    ' Return dialog's window handle.
    CreateContainer = hDlg
End Function

Function ContainerProc( hDlg, uMsg, wParam, lParam )
'-- Purpose:  Acts as container dialog box's dialog procedure (DLGPROC).
'             Forwards WM_COMMAND and WM_NOTIFY messages to the container's
'             parent window.

    Select Case uMsg
    Case _WM_COMMAND, _WM_NOTIFY
        CallDLL #user32, "GetParent", hDlg As ULong, hParent As Ulong
        CallDLL #user32, "SendMessageA", hParent As ULong,_
        uMsg As ULong, wParam As ULong, lParam As ULong, r As Long
    End Select
End Function

'***********************************************
' Support Procedures
'***********************************************

Function HIWORD( dw )
    HIWORD = (dw And 4294901760) / 65536
End Function

Function LOWORD( dw )
    LOWORD = (dw And 65535)
End Function

Function GetWindowLong( hWnd, Index )
    CallDLL #user32, "GetWindowLongA",_
    hWnd As ULong, Index As Long,_
    GetWindowLong As Long
End Function

Function MulDiv( Number, Numerator, Denominator )
    CallDLL #kernel32, "MulDiv", Number As Long,_
    Numerator As Long, Denominator As Long,_
    MulDiv As Long
End Function

Sub MoveWindow hWnd, X, Y
    flags = _SWP_NOZORDER Or _SWP_NOSIZE
    CallDLL #user32, "SetWindowPos", hWnd As ULong,_
    _NULL As ULong, X As Long, Y As Long, 0 As Long,_
    0 As Long, flags As Long, r As Long
End Sub

Sub SetParent hWnd, hNewParent
    CallDLL #user32, "SetParent", hWnd As ULong,_
     hNewParent As ULong, r As ULong
End Sub